* Cherry-pick several patches from the 1.3 branch: (LP: #976159)
- Add fix_misreported_marking_errors.diff to stop marking errors being
reported as lock errors.
- Add fix_worker_upgrade_marking.diff, which uses a more conservative
problem resolution method to fix marking issues that occur while
marking single packages for upgrade, as well as fixes an issue where
the worker would not clear errors caused by marking issues that had
been fixed manually.